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Home , Acronychia, Acronychia acidula, Araucaria bidwillii, Banksia ericifolia, Capsule (fruit), Caryopsis

Australian Society NORTH SHORE GROUP Ku-ring-gai Wildflower Garden

Flowers, and

FLOWERS

In common usage the word ‘’ is used for both a single flower and a number of flowers grouped together, for example a spike. Closer examination shows it is made up of single flowers, all with a similar structure.

A flower is the sexual reproductive of a , consisting of a that bears the , , and carpels – the four basic parts of a flower. Broadly speaking, the parts are in concentric rings.

Sepal: Makes up the outer ring, usually green and -like, and in the stage encloses and protects the other flower parts. Collectively known as the calyx. Sepals could be free, wholly or partly united, they could fall early or remain as part of the .

Petal: Makes up the next inner ring, usually conspicuous, brightly coloured, to attract . Collectively known as the corolla. They could also be free, part or fully united giving rise to variety of types.

Tepal: A free segment of a not recognized as a or a .

Perianth: Usually consisting of a of sepals and/or a whorl of petals, or two whorls of .

Pedicel: (stalk) of a flower, if not present the flower is sessile.

Female part of the flower

Gynoecium: the carpel (if solitary) or carpels of a flower. Carpel: A unit of the female of the flower, with an bearing one or more (female cells), usually a style (stalk), joining the ovary and a receptive of various shapes and size. A simple stigma has no structures present.

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A flower can have a solitary carpel or numerous carpels; these could be free or fused together. The ovules, if fertilized by compatible pollen, develop into , and the ovary into the fruit.

Male part of the flower

Androecium: consists of the stamens of a flower.

Stamen: A unit of the male organs of the flower, with an anther and often a filament or stalk. The anther, located at the terminal part of a , bears pollen sacs containing pollen (male cells).

Staminodes are sterile stamens which do not produce pollen, or the anthers are deformed or absent, in this case the filament may look like a petal. Anthers may open by longitudinal slits, valves or pores on the apex. They could be united, free, have appendages and be attached to filaments from the base, from the back or be pendulous.

Bract: A modified leaf, often small and associated with a flower or group of flowers

Bracteole(s): One or two -like structures on the stalk or on the calyx of a flower.

Hypanthium or Floral tube: The fused bases of perianth parts (calyx and /or corolla) and stamens. Usually a cup- like or tubular structure present in some flowers, for example Eucalypts and , which appear to be an upward growth from or part of the receptacle, of the edge of the ovary to casual observation.

Corolla tube: Formed by the basal section of petals being joined to each other. The throat is the top of the tube and the limb is the expanded part of the corolla, for example longiflora.

Free: Parts not joined together are called free.

Connate: Same parts of a flower joined together even for only part of their length; for example stamens in many of the pea flowers, or petals in the tubular corolla of .

Adnate : Similar to connate but different parts of the flower joined together, for example stamens joined to tepals as in some Banksia and in the .

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Superior ovary: Perianth and stamens are inserted on the receptacle below the ovary.

Inferior ovary: The receptacle is fused to the sides and often over the top of the ovary and the perianth and stamens are attached at the top of the ovary.

Half-inferior ovary occurs when the receptacle is fused only part of the way up the ovary wall.

Placentation: Arrangement of the ovules in the ovary

Regular flower (Actinomorphic): Perianth is radially symmetrical, the individual petals and sepals are alike. Perianth can be divided into equal parts by centrally cutting in more than one plane

Irregular flower (Zygomorphic): Petals and sepals are not alike. The perianth can be divided into 2 equal parts by cutting in one plane only.

Classification and naming of the flowering plants since Linnaeus in 1753 has been based on the structure of the flower. Parts of a flower may vary in number, size, colour, shape, arrangement and in having additional structures such as hairs, , spurs, hoods and . This variation is the basis of classification into species, although with modern technology genetic and protein analyses are now also used, together with ecology.

A flower at its most basic is a receptacle with carpel and/or stamens. In other words, a flower may not have petals or sepals, and it is then referred to as a naked flower.

Flowers that have a carpel and stamens are called bisexual. If the flower has only either a carpel or a stamen(s), it is called unisexual. Unisexual flowers may both (male and female) occur on the one plant (monoecious) or on separate male and female plants (dioecious).

Recommended reading Clarke, I. & Lee, H. Name that Flower. Melbourne University Press, Burwood, Vic. 2003. Harden, Gwen & Williams, John. How to Identify Plants. Univ. New England, Namoi.1990 Harden, Gwen & Murray, Louisa H. Supplement to of NSW Vol 1. UNSW Press, Royal Botanic Gardens, . 2020.

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INFLORESCENCES

Did you know that,

• An is the flowering shoot of a plant. • It can range from a single flower to a very complex arrangement of many flowers. • A Banksia ‘flower’ or a Telopea () ‘flower’ is such a group of many individual flowers with similar flower structure.

The stalk of an individual flower is called a . The main stalk of an inflorescence is a . Individual flowers may be called pedicellate (with a stalk) or sessile (without a stalk). The stem-like flowering stalk of a plant with clustered at the base is a scape. In the diagrams, a circle represents a flower bud and an arrow represents a vegetative bud.

A single flower is described as solitary. The flowering shoot is called an inflorescence:

Solitary on scape Spike: e.g. many species flowers sessile e.g. sp.

Solitary in leaf axil : (the angle between the flowers pedicellate leaf and the stem) e.g. Hardenbergia e.g. ledifolia violacea

An inflorescence which has internal branching is called a compound inflorescence

Panicle: main axis has branches which may be further branched e.g. Dianella sp.

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Corymb: Spadix: all the flowers are at the a spike with a thickened same level though the axis being surrounded by pedicels arise at different a spathe e.g. Alocasia levels e.g. sp. brisbanensis

Head: : a dense cluster of a group of reduced more or less sessile flowers unisexual flowers e.g. a group of surrounded by a whorl florets sessile on a common of bracts e.g. receptacle sp.

Umbel: Spikelet: All flowers arise from an axis bearing glumes one point at the top of enclosing florets e.g. the peduncle (grasses) e.g. Actinotus sp.

Compound : Invaginated inflorescence branched umbel a pocket formed by turning e.g. Platysace sp. in on itself e.g. spp. where the minute flowers and fruits are actually inside the axis

Inflorescences can be described as racemose or cymose. In most inflorescences the oldest flowers are at the base and end in a vegetative (non-floral) bud thus allowing further growth of the axis: these are called racemose inflorescences. However, in others the flower terminates the axis and expansion takes place through the growth of axillary which also end in a flower, these are called cymose.

Types of cyme Mixed type:

Monochasial cyme: Thyrse:

a cyme with the branches a compound inflorescence

arising singly ending in a vegetative bud

i.e. racemose, but with Dichasial cyme: lateral branches ending in a cyme with the branches a flower i.e. cymose e.g. arising in opposite pairs ovata

Acknowledgments: These notes contain hyperlinks to materials, including images, illustrations, plant descriptions and a glossary from PlantNET, with the courtesy of The Royal Botanic Gardens & Domain Trust, 2020. For general access to PlantNET see also http://plantnet.rbgsyd.nsw.gov.au/

Revised 2020/WG for Australian Plants Society North Shore Group, Walks & Talks Program.

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IDENTIFYING PLANTS BY THEIR FRUITS

Did you know that,

• The fruit of the Blueberry Ash is not a . • The fruit of the is not a . • The fruit of a Banksia is not a cone. • Some fruits are poisonous.

Introduction

A fruit is the -bearing structure of a plant whether fleshy or dry. These fruits or seed cases and the seeds they contain are the most complex structures plants produce. They are the essential elements which ensure the continuation of the species and it is the only phase in the life of most plants when they can travel. Dispersal is a key element in plant survival and many plants have evolved methods to ensure the seeds are dispersed. For example, through the succulent fruit eaten and dispersed by animals or the exploding pods of , to the winged seeds contained in many seed cases and the burrs which can travel in an animal’s fur.

Do not eat fruits that you do not know to be safe to eat.

We are going to look at the ways plants package their seeds to ensure survival and this will help in the identification and classification of native plants.

Following are some useful terms which will be used in this talk.

Glossary

Carpel: The female part of a flower consisting of the stigma, style and ovary

Cauliflory: The production of flowers or fruits on well-developed trunks and branches

Dehiscent: Opening on maturity to release the seed

Indehiscent: Not opening on maturity to release seed

Dioecious: With male and female flowers on separate plants

Monoecious: Having male and female flowers on the same plant

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Native Fruits and other Seed Cases

Fruit type/ Description Native Plant Seed Case example

Drupe An indehiscent (not opening) succulent fruit derived from one or more carpels in jerseyana, which the pericarp consists of three (Davidson’s Plum), layers: the seed(s) enclosed in the inner acidula, stony layer – ENDOCARP, a soft fleshy (Lemon Aspen), layer MESOCARP and an outer skin EPICARP. reticulatus, (Blueberry Ash), pinifolia, (Geebung).

Aggregate A cluster of individual drupelets derived Rubus rosifolius, from a single flower in which the carpels (Native Raspberry). are free from each other. Although commonly referred to as e.g. raspberry, blackberry, these are not berries.

Berry A fleshy indehiscent fruit with one or more laurina, seeds embedded in the fleshy with (Bolwarra), no endocarp. May be formed from either a Cordyline rubra, superior or inferior ovary e.g. ovary above Dianella caerulea, floral parts or ovary below floral parts. Syzygium australe. Berries change colour and become soft as they ripen.

Follicle A dry fruit derived from a single carpel and opening along one side. In sinuatus, (Firewheel the fruits are actually a number of ), Grevillea individual follicles joined together on a hilliana, woody cone. Some fruit have winged gibbosa, Banksia seeds e.g. Hakea. In some , Banksia species follicles open after bush fires e.g. ericifolia, B. serrata, B. ericifolia. .

Syconium The formed in figs where the Ficus leptoclada, minute flowers and fruits are actually (Cauliflory Fig), inside the swollen inflorescence stem. The Ficus coronata, flowers are pollinated by wasps specific to (Sandpaper Fig). each species. Some fig species produce fruit on the trunk and major branches. This process is called cauliflory e.g. Ficus leptoclada. The mature fruit of the fig are eaten by birds and animals and dispersed.

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Grain or Grains are single seeded fruits produced Themeda australis, by grasses. Flowers of these species are (Kangaroo Grass). insignificant and usually in large flower heads that occur on tall stems. In most cases each flower head will develop to contain many individual grains. Grains become dry, change in colour from green to brown and release easily from the plant when mature. In Themeda australis each has a bristle-like attachment called an awn. The awn acts to ‘screw’ the grain into the ground.

Woody A dry dehiscent fruit that usually contains spp., several or numerous seeds. Capsules take Xanthorrhoea from 4 to 24 months to reach maturity media, after flowering. They become dry, hard Callistemon and woody when the seed is mature. viminalis, Seeds are released from valves on the Leptospermum tops of capsules. The seed is usually small squarrosum, and various shades of brown or black. hypericifolia.

Non- Many Australian native plants contain seed Lomandra longifolia, woody in non-woody capsules. These capsules capsule range from papery and brittle to leathery revolutum, or slightly woody. Non-woody capsules Auranticarpa usually open to release seed soon after rhombifolia, Toona maturity. Depending on the species each ciliata. capsule contains 2-10 seeds ranging from dust-like to 2-3mm in diameter.

Specialized scale-like structures bearing bidwillii, the seeds arranged tightly on a central (Bunya ), axis. Plants with cones do not produce Cone flowers, instead the seeds develop on the communis, scale-like structures that eventually form (Burrawang). the cones.

Pod or A long dry dehiscent fruit formed from one Castanospermum carpel and opening down two sides. australe, Depending on the species pods range from (Black Bean), papery to leathery at maturity. As pods Acacia spp. mature, they change colour from green to various shades of brown or black and become dry and brittle. Pods split down both sides to release seed upon maturity. Pods of some species open explosively during hot weather.

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A selection of Species found at Ku-ring-gai Wildflower Garden SCIENTIFIC NAME COMMON NAME SEED CASE TYPE Blueberry Ash Drupe Broad-leaved Geebung Drupe Pine-leaved Geebung Drupe Drupe Red Bopple Nut pinnatifolia Davidsonia jerseyana Davidson’s Plum Drupe Trochocarpa laurina Tree Drupe Dianella caerulea Lily Berry Bolwarra Berry Syzygium australe Brush Cherry Berry Firewheel Tree Follicle Ivory Curl Tree celsissima Macadamia tetraphylla Macadamia Nut Follicle Banksia serrata Saw-tooth Banksia Follicle Heath Banksia Follicle Waratah Follicle Needle Bush Follicle Pink Spider Flower Follicle Fine-leaved Grevillea Follicle Ficus coronata Sandpaper Fig Port Jackson Fig Syconium Themeda australis Kangaroo Grass Grain or Caryopsis Xanthorrhoea sp. Grass Tree Woody capsule Eucalyptus Woody capsule Scribbly Gum haemastoma Callistemon viminalis Weeping Bottle Brush Woody capsule Lomandra longifolia Mat Rush Non-Woody capsule Auranticarpa rhombifolia Holly-leaved Non-Woody capsule Pittosporum Pittosporum revolutum Rough fruit Pittosporum Non-Woody capsule Toona ciliata Red Cedar Non-Woody capsule Bunya Pine Cone Araucaria cunninghamii Hoop Pine Cone Burrawang Cone Scrub or Black She-oak Casuarina glauca Swamp Oak Samara Castanospermum Pod or Legume Black Bean australe Indigofera australis Native Indigo Pod or Legume Acacia sp. Wattle Pod or Legume Morinda jasminoides Sweet Morinda Syncarp Gahnia sp. Saw Sedge Nut Produced for Australian Plants Society-North Shore Group by David Chandler 2015 Acknowledgments: These notes may contain hyperlinks and materials, including images, illustrations, plant descriptions and a glossary from PlantNET, with the courtesy of The Royal Botanic Gardens & Domain Trust, 2020. See also http://plantnet.rbgsyd.nsw.gov.au/

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